In the scientific fields it is often necessary to manipulate fluid flow through conduits by opening, closing and diverting fluid flow to transport or mix various fluids from various sources. The most common example of this occurs in medicine where medicament (medication or fluid) infusing into a patient via an intravenous or central line) need to be mixed with another infusing medicament in a way that can be manipulated so as to allow or disallow the various infusions as required. These same fluid systems need to allow the practitioner direct sterile access so that a given medicine or fluid may be directly injected, pressure may be directly monitored, or body fluid may be directly removed for sampling.
A common way to accomplish this is through the use of medical stopcocks which are most commonly of the “3 way type” or less commonly “4 way type” (these stopcocks are shown in FIG. 1). These inventions allow ports to be opened or closed as need be to allow or disallow the flow of a given medicament or to allow direct access to the fluid system for the above stated reasons.
A common problem with the use of these 3 and 4 way medical stopcocks is the manipulation or setting of their flow patterns (operable or functional state) based on one's visual assessment. The user must rotate a central hub to align flow through the desired ports based on his or her ability to understand and interpret the functionality of the stopcock. This functionality is most commonly delineated by a single knob which points to the port that is closed, making interpretation of those that are open difficult. This lack of positive delineation leads to misinterpretation of flow patterns with concomitant errors in settings and associated medication errors which may lead to harm or death.
The difficulty in interpreting the flows that will be allowed from a given setting also limits the number of combinations (i.e. 4 way). This limit occurs because with stopcocks that offer more than four combinations (i.e. 4 way), interpretation and manipulation become too complicated and the chances for error increase exponentially. This limits the current technology and requires assembling two or more of the standard stopcocks in series (an arrangement known as a “manifold”) if more choices are required. This increases cost, complexity and each stopcock in the chain multiplies the chance of medication errors.